linux-kernel - [RFC PATCH 0/3] drm/imagination: add AM62P/AM67A/J722S support

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Message-Id: <20250716134717.4085567-1-mwalle@kernel.org>
Date: Wed, 16 Jul 2025 15:47:14 +0200
From: Michael Walle <mwalle@...nel.org>
To: Frank Binns <frank.binns@...tec.com>,
	Matt Coster <matt.coster@...tec.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Nishanth Menon <nm@...com>,
	Vignesh Raghavendra <vigneshr@...com>,
	Tero Kristo <kristo@...nel.org>
Cc: dri-devel@...ts.freedesktop.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Michael Walle <mwalle@...nel.org>
Subject: [RFC PATCH 0/3] drm/imagination: add AM62P/AM67A/J722S support

The AM62P and AM67A/J722S feature the same BXS-4 GPU as the J721S2.
In theory, one have to just add the DT node. But it turns out, that
the clock handling is not working. If I understood Nishan Menon
correct, it is working on the J721S2 because there, the clock is
shared, while on the AM62P the GPU has its own PLL.
In the latter case, the '#assigned-clocks' property of the GPU node
doesn't work properly. Linux will try to set the clock frequency
before probing the GPU. The clock handling firmware on the SoC won't
allow that if there is no user for it. To work around that
limitation, set the clock again in the .probe() of the GPU driver
after turning the device on.

This was tested on an AM67A.

Michael Walle (3):
  dt-bindings: gpu: img: Add AM62P SoC specific compatible
  drm/imagination: fix clock control on the J722S
  arm64: dts: ti: add GPU node

 .../devicetree/bindings/gpu/img,powervr-rogue.yaml  |  1 +
 .../boot/dts/ti/k3-am62p-j722s-common-main.dtsi     | 13 +++++++++++++
 drivers/gpu/drm/imagination/pvr_device.c            |  9 +++++++++
 3 files changed, 23 insertions(+)

-- 
2.39.5